[PATCH 0/2] selftests: ALSA: pcmtest: Fix two test bugs

[PATCH 0/2] selftests: ALSA: pcmtest: Fix two test bugs

[HyeongJun An]

Two fixes for the pcmtest selftest. The first makes the playback tests
fail when a transfer fails. The second sizes the pattern buffer to the
4096 bytes the driver allows.

Tested on x86_64 with snd-pcmtest. All five tests pass as before. With
inject_trigger_err=1 the playback and ni_playback tests passed before
and now fail. With a 2000-byte pattern on channel 0 four tests failed
before and now pass.

HyeongJun An (2):
  selftests: ALSA: pcmtest: Check the frame count of each transfer
  selftests: ALSA: pcmtest: Make room for the longest fill pattern

 .../selftests/alsa/test-pcmtest-driver.c      | 25 +++++++++++--------
 1 file changed, 15 insertions(+), 10 deletions(-)

-- 
2.43.0

[PATCH 1/2] selftests: ALSA: pcmtest: Check the frame count of each transfer

[HyeongJun An]

The tests keep the result of snd_pcm_writei(), snd_pcm_readi() and
their non-interleaved forms in a size_t. A size_t is never negative, so
ASSERT_GE(res, 0) always passes.

The capture tests still catch a failed read when they compare the data.
But the playback tests do not. The driver sets pc_test to 1 when it saw
no corrupted data, and that is also true when it saw no data at all. So
a playback test passes even when every write fails.

Store the result as snd_pcm_sframes_t and check that the whole request
was transferred. The calls block, so a short count means an error.

Fixes: 10b98a4db11a ("selftests: ALSA: Add test for the 'pcmtest' driver")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
---
 .../selftests/alsa/test-pcmtest-driver.c      | 21 +++++++++++--------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/alsa/test-pcmtest-driver.c b/tools/testing/selftests/alsa/test-pcmtest-driver.c
index 95065ef3b441..5bba17434a6b 100644
--- a/tools/testing/selftests/alsa/test-pcmtest-driver.c
+++ b/tools/testing/selftests/alsa/test-pcmtest-driver.c
@@ -166,7 +166,7 @@ FIXTURE_SETUP(pcmtest) {
 TEST_F(pcmtest, playback) {
 	snd_pcm_t *handle;
 	unsigned char *it;
-	size_t write_res;
+	snd_pcm_sframes_t write_res;
 	int test_results;
 	int i, cur_ch, pos_in_ch;
 	void *samples;
@@ -190,7 +190,7 @@ TEST_F(pcmtest, playback) {
 		it[i] = patterns[cur_ch].buf[pos_in_ch % patterns[cur_ch].len];
 	}
 	write_res = snd_pcm_writei(handle, samples, params->rate * params->time);
-	ASSERT_GE(write_res, 0);
+	ASSERT_EQ(write_res, params->rate * params->time);
 
 	snd_pcm_close(handle);
 	free(samples);
@@ -206,7 +206,7 @@ TEST_F(pcmtest, playback) {
 TEST_F(pcmtest, capture) {
 	snd_pcm_t *handle;
 	unsigned char *it;
-	size_t read_res;
+	snd_pcm_sframes_t read_res;
 	int i, cur_ch, pos_in_ch;
 	void *samples;
 	struct pcmtest_test_params *params = &self->params;
@@ -222,7 +222,7 @@ TEST_F(pcmtest, capture) {
 	snd_pcm_format_set_silence(params->format, samples,
 				   params->rate * params->channels * params->time);
 	read_res = snd_pcm_readi(handle, samples, params->rate * params->time);
-	ASSERT_GE(read_res, 0);
+	ASSERT_EQ(read_res, params->rate * params->time);
 	snd_pcm_close(handle);
 	it = (unsigned char *)samples;
 	for (i = 0; i < self->params.sec_buf_len * self->params.time; i++) {
@@ -239,7 +239,8 @@ TEST_F(pcmtest, ni_capture) {
 	snd_pcm_t *handle;
 	struct pcmtest_test_params params = self->params;
 	char **chan_samples;
-	size_t i, j, read_res;
+	snd_pcm_sframes_t read_res;
+	size_t i, j;
 
 	chan_samples = calloc(CH_NUM, sizeof(*chan_samples));
 	ASSERT_NE(chan_samples, NULL);
@@ -257,7 +258,7 @@ TEST_F(pcmtest, ni_capture) {
 
 	for (i = 0; i < 1; i++) {
 		read_res = snd_pcm_readn(handle, (void **)chan_samples, params.rate * params.time);
-		ASSERT_GE(read_res, 0);
+		ASSERT_EQ(read_res, params.rate * params.time);
 	}
 	snd_pcm_close(handle);
 
@@ -273,7 +274,8 @@ TEST_F(pcmtest, ni_playback) {
 	snd_pcm_t *handle;
 	struct pcmtest_test_params params = self->params;
 	char **chan_samples;
-	size_t i, j, read_res;
+	snd_pcm_sframes_t write_res;
+	size_t i, j;
 	int test_res;
 
 	chan_samples = calloc(CH_NUM, sizeof(*chan_samples));
@@ -294,8 +296,9 @@ TEST_F(pcmtest, ni_playback) {
 	}
 
 	for (i = 0; i < 1; i++) {
-		read_res = snd_pcm_writen(handle, (void **)chan_samples, params.rate * params.time);
-		ASSERT_GE(read_res, 0);
+		write_res = snd_pcm_writen(handle, (void **)chan_samples,
+					   params.rate * params.time);
+		ASSERT_EQ(write_res, params.rate * params.time);
 	}
 
 	snd_pcm_close(handle);
-- 
2.43.0

[PATCH 2/2] selftests: ALSA: pcmtest: Make room for the longest fill pattern

[HyeongJun An]

The driver accepts fill patterns of up to 4096 bytes, as pcmtest.rst
documents. The test reads each pattern into a 1024-byte buffer, using
the length the driver reports. So a pattern longer than 1024 bytes
overflows the buffer into the next pattern and past the array.

Size the buffer to the driver's maximum.

Fixes: 10b98a4db11a ("selftests: ALSA: Add test for the 'pcmtest' driver")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: HyeongJun An <sammiee5311@gmail.com>
---
 tools/testing/selftests/alsa/test-pcmtest-driver.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/alsa/test-pcmtest-driver.c b/tools/testing/selftests/alsa/test-pcmtest-driver.c
index 5bba17434a6b..e025a7bac26b 100644
--- a/tools/testing/selftests/alsa/test-pcmtest-driver.c
+++ b/tools/testing/selftests/alsa/test-pcmtest-driver.c
@@ -10,9 +10,11 @@
 #include "kselftest_harness.h"
 
 #define CH_NUM 4
+/* The driver accepts patterns of up to 4096 bytes */
+#define MAX_PATTERN_LEN 4096
 
 struct pattern_buf {
-	char buf[1024];
+	char buf[MAX_PATTERN_LEN];
 	int len;
 };
 
-- 
2.43.0

Re: [PATCH 0/2] selftests: ALSA: pcmtest: Fix two test bugs

[Takashi Iwai]

On Tue, 20 Oct 2026 12:18:35 +0200,
HyeongJun An wrote:
> 
> Two fixes for the pcmtest selftest. The first makes the playback tests
> fail when a transfer fails. The second sizes the pattern buffer to the
> 4096 bytes the driver allows.
> 
> Tested on x86_64 with snd-pcmtest. All five tests pass as before. With
> inject_trigger_err=1 the playback and ni_playback tests passed before
> and now fail. With a 2000-byte pattern on channel 0 four tests failed
> before and now pass.
> 
> HyeongJun An (2):
>   selftests: ALSA: pcmtest: Check the frame count of each transfer
>   selftests: ALSA: pcmtest: Make room for the longest fill pattern

Applied both patches.  Thanks.


Takashi